Policy decision function addressing method, network element and network system

ABSTRACT

A policy decision function (PDF) addressing method includes: receiving a PDF allocation request that contains a user equipment (UE) identifier (ID) from a second network element (NE); obtaining ID information of a PDF associated with the UE ID according to pre-registered addressing information of the PDF, where the addressing information of the PDF is an association between the UE ID and the ID information of the PDF, and the PDF associated with the UE ID is accessed by a first NE; and sending the obtained ID information of the PDF to the second NE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/749,039, filed Mar. 29, 2010, which is a continuation ofInternational Patent Application No. PCT/CN2008/072521, filed on Sep.25, 2008. The International Patent Application claims priority toChinese Patent Application No. 200710151383.2, filed on Sep. 30, 2007,and Chinese Patent Application No. 200710166427.9, filed on Oct. 31,2007, all of which are hereby incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a communication technology, and inparticular, to a policy decision function (PDF) addressing method, anetwork element (NE) and a network system.

BACKGROUND OF THE INVENTION

In a current network system, the policy and charging control (PCC)protocol is used to exercise quality of service (QoS) control andcharging control over data services between a user equipment (UE) and apacket data network gateway. A PDF is an entity used to generate policycontrol information for exercising QoS control and charging control overdata services. A gateway (access gateway or packet data network gateway)is a policy enforcement point (PEP). The gateway obtains policy controlinformation from the PDF, and then exercises QoS control and chargingcontrol over data services between the UE and the packet data gateway(also called a public data network gateway, PDN GW) according to theobtained policy control information.

In the prior art, the UE may require two data connections: one isconnected to gateway 1 and the other is connected to gateway 2. Gateway1 and gateway 2 access a PDF according to the UE identifier (UE ID) andID of a public data network (PDN). Gateway 1 and gateway 2 may notaccess the same PDF.

During the research and practice of the prior art, the inventordiscovers the following problems:

In the technical solution of the prior art, NEs that want to access aPDF cannot access the same PDF in the data connection of the same UE.

SUMMARY OF THE INVENTION

The objective of embodiments of the present invention is to provide apolicy decision function (PDF) addressing method, a network element (NE)and a network system to ensure NEs that want to access a PDF can accessthe same PDF in the data connection of the same UE.

To achieve the preceding objective, embodiments of the present inventionprovide the following technical solutions:

A PDF addressing method includes:

receiving a PDF allocation request that contains a UE identifier (UE ID)from a second NE;

obtaining ID information of a PDF associated with the UE ID according topre-registered addressing information of the PDF, where the addressinginformation of the PDF is an association between the UE ID and the IDinformation of the PDF and the PDF associated with the UE ID is accessedby a first NE; and

sending the obtained ID information of the PDF to the second NE.

An NE includes:

a PDF request receiving unit, configured to receive a PDF allocationrequest that contains a UE ID;

a PDF ID information obtaining unit, configured to obtain ID informationof a PDF associated with the UE ID according to pre-registeredaddressing information of the PDF, where the addressing information ofthe PDF is an association between the UE ID and the ID information ofthe PDF, and the PDF associated with the UE ID is accessed by a firstNE; and

a PDF ID information outputting unit, configured to output the obtainedID information of the PDF.

A network system includes a policy management entity (PME) and a secondNE, where:

the PME is configured to: receive a PDF allocation request that containsa UE ID from a second NE; obtain ID information of a PDF associated withthe UE ID according to pre-registered addressing information of the PDF,where the addressing information of the PDF is an association betweenthe UE ID and the ID information of the PDF and the PDF associated withthe UE ID is accessed by a first NE; and send the obtained IDinformation of the PDF to the second NE; and

the second NE is configured to: send the PDF allocation request to thePME, and receive the ID information of the PDF sent from the PME.

Any of the preceding technical solutions may bring the followingbenefits:

In embodiments of the present invention, after a PDF allocation requestis received from the second NE, the ID information of the PDF associatedwith the UE ID is obtained according to the pre-registered addressinginformation of the PDF, that is, ID information of the PDF accessed bythe first NE, and then the obtained ID information of the PDF is sent tothe second NE so that the second NE and the first NE access the samePDF. Thus, for the data connection of the same UE, different NEs thatwant to access a PDF may access the same PDF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a PDF addressing method according to a firstembodiment of the present invention;

FIG. 2 is a flowchart of a PDF addressing method according to a secondembodiment of the present invention;

FIG. 3 is a flowchart of a PDF addressing method according to a thirdembodiment of the present invention;

FIG. 4 is a flowchart of a PDF addressing method according to a fourthembodiment of the present invention;

FIG. 5 is a flowchart of a PDF addressing method according to a fifthembodiment of the present invention;

FIG. 6 is a flowchart of a PDF addressing method according to a sixthembodiment of the present invention;

FIG. 7 is a flowchart of a PDF addressing method according to a seventhembodiment of the present invention;

FIG. 8 is a flowchart of a PDF addressing method according to an eighthembodiment of the present invention;

FIG. 9 is a flowchart of a PDF addressing method according to a ninthembodiment of the present invention;

FIG. 10 is a flowchart of a PDF addressing method according to a tenthembodiment of the present invention;

FIG. 11 is a flowchart of a PDF addressing method according to aneleventh embodiment of the present invention;

FIG. 12 shows a structure of an NE according to a twelfth embodiment ofthe present invention;

FIG. 13 shows a structure of an NE according to a thirteenth embodimentof the present invention; and

FIG. 14 shows a structure of an NE according to a fourteenth embodimentof the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A PDF addressing method according to an embodiment of the presentinvention includes: receiving a PDF allocation request that contains aUE ID from a second NE; obtaining ID information of a PDF associatedwith the UE ID according to pre-registered addressing information of thePDF, where the addressing information of the PDF is an associationbetween the UE ID and the ID information of the PDF, and the PDFassociated with the UE ID is accessed by a first NE; and sending theobtained ID information of the PDF to the second NE. The ID informationof the PDF may be the domain name and/or address information of the PDF.The first NE may be an access gateway, a PDN GW or a PDF in a visitednetwork (also referred to as “visited PDF” hereunder). The second NE maybe an access gateway, a PDN GW, a visited PDF or an applicationfunction. The access gateway and PDN GW are PEPs.

FIG. 1 shows a PDF addressing method according to the first embodimentof the present invention. The method is applicable to scenarios where anon-3GPP access network is used on a 3GPP system architecture evolution(SAE) network. The access gateway of the non-3GPP access network is thePEP of the non-3GPP access network. The PDN GW is the core gateway ofthe SAE network. Being the PEP of a core network, the PDF is responsiblefor generating policy control information. The PDF may also integratecharging functions to work as a policy and charging rules function(PCRF). In this embodiment, the PDF may or may not integrate thecharging control function. In this method, the UE first sets up a localconnection in the local network, and then sets up a data connection withthe PDN GW. A PME is added. The PME is configured to maintain addressinginformation of the PCRF. The method includes the following steps:

Step 101: The UE sends a local connection setup request to the accessgateway.

Step 102: The access gateway interacts with the PME to request theaddress of the PCRF.

Specifically, this step is as follows: The access gateway sends a PDFaddress allocation request to the PME, where the request contains the UEID, or UE ID and PDN ID; the PME searches for the address of a matchingPDF according to the UE ID, or UE ID and PDN ID; if finding the matchingPDF, the PME returns the address of the PDF to the access gateway;otherwise, the PME allocates a proper PDF for the UE, and returns theaddress of the allocated PDF to the access gateway, or the PME returns aPCRF address request failure to the access gateway to inform the accessgateway of selecting its own PCRF. The preceding returned address of thePDF is the address of the PCRF.

Step 103: The access gateway interacts with the PCRF to obtain policycontrol information.

In this step, the access gateway finds the PCRF according to the addressof the PCRF sent from the PME, and obtains the policy controlinformation from the PCRF. If the PME returns a PCRF address requestfailure to the access gateway, the access gateway selects a proper PCRFand obtains the policy control information from the selected PCRF.

Step 104: The access gateway registers the addressing information of thePCRF with the PME.

The addressing information of the PCRF may be an association between theUE ID and the address of the PCRF or an association among the UE ID, thePDN ID and the PCRF.

Specifically, step 104 is as follows: The access gateway sends aregistration request containing the addressing information of the PCRFto the PME, and the PME registers the addressing information of thePCRF.

If the PME does not find a matching PDF in step 102, the PME allocates aproper PDF for the UE, or the PME returns a PCRF address request failureto the access gateway to inform the access gateway of selecting its ownPCRF, the access gateway needs to select a proper PCRF before step 103and step 104.

If the PME finds the matching PCRF according to the UE ID or UE ID andPDN ID and sends the address of the PCRF to the access gateway orallocates an address of a PCRF for the access gateway in step 102, thePME may store the addressing information of the PCRF in step 102. Inthis case, step 104 is optional.

Step 105: The access gateway sends an acknowledgement message indicatingthe completion of local connection setup to the UE.

Step 106: The UE sends a data connection setup request to the PDN GW.

Step 107: The PDN GW accesses the PME to request the address of thePCRF, and the PME sends the address of the PCRF to the PDN GW.

Specifically, this step is as follows: The PDN GW sends a request forthe address of the PDF to the PME, where the request contains the UE ID;the PME obtains the address of the PCRF associated with the UE IDaccording to the pre-registered addressing information of the PCRF, andsends the address of the PCRF to the PDN GW.

Step 108: The PDN GW interacts with the PCRF to obtain policy controlinformation.

Step 109: The PDN GW sends an acknowledgement message indicating thecompletion of data connection setup to the UE.

In the first embodiment of the present invention, after receiving thePDF address allocation request from the PDN GW, the PME obtains theaddress of the PDF associated with the UE ID (address of the PDFaccessed by the access gateway) according to the pre-registeredaddressing information of the PDF; the PME then sends the obtainedaddress of the PDF to the PDN GW. Thus, the PDN GW and the accessgateway can access the same PDF to exercise policy control over datastreams in the data connection of the same UE.

FIG. 2 shows a PDF addressing method according to the second embodimentof the present invention. The method is applicable to a mobile network,with more than two PEPs. Each PEP needs to interact with the PDF toobtain policy control information. That is, a same IP-connectivityaccess network (IP-CAN) is connected to a same PDF. The method describesthe data connection process supposing the access gateway and coregateway are PEPs. The PDF addressing method includes the followingsteps:

Step 201: The UE sends a connection setup request to the access gateway.

Step 202: The access gateway interacts with the PME to request theaddress of the PDF.

Specifically, this step is as follows: The access gateway sends a PDFaddress allocation request to the PME, where the request contains the UEID, or UE ID and PDN ID; the PME searches for a matching PDF accordingto the UE ID, or UE ID and PDN ID; if finding the matching PDF, the PMEreturns the address of the PDF to the access gateway; otherwise, the PMEallocates the UE one or multiple proper PDFs for the access gateway toselect, and returns the address of the allocated PDF to the accessgateway, or the PME returns a request failure to the access gateway toinform the access gateway of selecting PDF by itself.

Step 203: The access gateway interacts with the PDF to obtain policycontrol information.

Step 204: The access gateway registers the addressing information of thePDF with the PME.

Step 204 is mandatory if the access gateway selects its own PDF in step202 and step 203; otherwise, step 204 is optional and the PME mayregister the addressing information of the PDF automatically afterallocating the address of the PDF.

The addressing information of the PDF is an association between the UEID and the address of the PDF, or an association among the UE ID, thePDN ID and the address of the PDF.

Step 205: The access gateway sends a connection setup request to thecore gateway.

Step 206: The core gateway interacts with the PME to request the addressof the PDF.

Specifically, this step is as follows: The core gateway sends a PDFaddress allocation request to the PME, which contains the UE ID; the PMEobtains the address of the PDF associated with the UE ID according tothe pre-registered addressing information of the PDF, and sends theobtained address of the PDF to the core gateway.

Step 207: The core gateway interacts with the PDF to obtain policycontrol information.

Step 208: The core gateway sends an acknowledgement message indicatingthe completion of connection setup to the access gateway.

Step 209: The access gateway sends an acknowledgement message indicatingthe completion of connection setup to the UE.

In the second embodiment of the present invention, after receiving thePDF address allocation request from the core gateway, the PME obtainsthe address of the PDF associated with the UE ID (address of the PDFaccessed by the access gateway) according to the pre-registeredaddressing information of the PDF; the PME then sends the obtainedaddress of the PDF to the core gateway. Thus, the core gateway and theaccess gateway can access the same PDF to exercise policy control overdata streams in the data connection of the same UE.

FIG. 3 shows a PDF addressing method according to the third embodimentof the present invention. The difference between the third embodimentand the second embodiment is as follows: The core network interacts withthe PDF, and then registers the addressing information of the PDF withthe PME. The method includes the following steps:

Step 301: The UE sends a connection setup request to the access gateway.

Step 302: The access gateway sends a connection setup request to thecore gateway.

Step 303: The core gateway interacts with the PME to request the addressof the PDF.

Specifically, this step is as follows: The core gateway sends a PDFaddress allocation request to the PME, where the request contains the UEID, or UE ID and PDN ID; the PME searches for a matching PDF accordingto the UE ID, or UE ID and PDN ID; if finding the matching PDF, the PMEreturns the address of the PDF to the core gateway; otherwise, the PMEallocates the UE with one or multiple proper PDFs for the core gatewayto select, and returns the address of the allocated PDF to the coregateway, or the PME returns a request failure to the core gateway toinform the core gateway of select PDF by itself.

This step may also be omitted. In this case, the core network selectsits own PDF, but step 305 needs to be executed.

Step 304: The core gateway interacts with the PDF to obtain policycontrol information.

Step 305: The core gateway registers the addressing information of thePDF with the PME.

Step 305 is mandatory if the core network selects its own PDF andinteracts with the PDF to obtain policy control information in step 304;otherwise, step 305 is optional and the PME may register the addressinginformation of the PDF automatically after allocating the address of thePDF.

Step 306: The core gateway sends an acknowledgement message indicatingthe completion of connection setup to the access gateway.

Step 307: The access gateway interacts with the PME to request theaddress of the PDF.

Specifically, this step is as follows: The access gateway sends a PDFaddress allocation request to the PME, which contains the UE ID, or UEID and PDN ID; the PME obtains the address of the PCRF associated withthe UE ID, or UE ID and PDN ID according to the pre-registeredaddressing information of the PCRF, and sends the obtained address ofthe PCRF to the access gateway.

Step 308: The access gateway interacts with the PDF to obtain policycontrol information.

Step 309: The access gateway sends an acknowledgement message indicatingthe completion of connection setup to the UE.

In the third embodiment of the present invention, after receiving thePDF address allocation request from the access gateway, the PME obtainsthe address of the PDF associated with the UE ID (address of the PDFaccessed by the access gateway) according to the pre-registeredaddressing information of the PDF; the PME then sends the obtainedaddress of the PDF to the access gateway. Thus, the core gateway and theaccess gateway can access the same PDF to exercise policy control overdata streams in the data connection of the same UE.

FIG. 4 shows a PDF addressing method according to the fourth embodimentof the present invention. The difference between the fourth embodimentand the third embodiment is as follows: The core network interacts withthe PDF, and then registers the addressing information of the PDF withthe PME, where the addressing information of the PDF is an associationbetween the UE ID and the domain name of the PDF. The method includesthe following steps:

Step 401: The UE sends a connection setup request to the access gateway.

Step 402: The access gateway sends a connection setup request to thecore gateway.

Step 403: The core gateway interacts with the PME, requesting the PME toallocate a PDF.

Specifically, this step is as follows: The core gateway sends a PDFallocation request to the PME, which contains the UE ID, or UE ID andPDN ID; the PME searches for a matching PDF according to the UE ID, orUE ID and PDN ID; if finding the matching PDF, the PME returns thedomain name of the PDF to the core gateway; otherwise, the PME allocatesthe UE one or multiple proper PDFs for the core gateway to select, andreturns the domain name of the allocated PDF to the core gateway, or thePME returns a request failure to the core gateway to inform the coregateway of selecting PDF by itself

This step may also be omitted. In this case, the core network selectsits own PDF, but step 405 needs to be executed.

Step 404: The core gateway interacts with the PDF to obtain policycontrol information.

Step 405: The core gateway registers the addressing information of thePDF with the PME.

Step 405 is mandatory if the core network selects its own PDF andinteracts with the PDF to obtain policy control information in step 404;otherwise, step 405 is optional and the PME may register the addressinginformation of the PDF automatically after allocating the PDF.

Step 406: The core gateway sends an acknowledgement message indicatingthe completion of connection setup to the access gateway.

Step 407: The access gateway interacts with the PME, requesting the PMEto allocate a PDF, and the PME returns the domain name of the PDF to theaccess gateway.

Specifically, this step is as follows: The access gateway sends a PDFallocation request to the PME, which contains the UE ID, or UE ID andPDN ID; the PME obtains the domain name of the PDF associated with theUE ID, or UE ID and PDN ID according to the pre-registered addressinginformation of the PDF, and sends the obtained domain name of the PDF tothe access gateway.

Step 408: The access gateway receives the domain name of the PDF, andresolves the address information of the PDF associated with the domainname through the domain name resolution service.

Step 409: The access gateway interacts with the PDF to obtain policycontrol information.

In this embodiment, the access gateway may also not resolve the addressinformation associated with the domain name of the PDF. Instead, theaccess gateway sends the domain name of the PDF to an agent (forexample, a relay agent and a proxy agent). Then, the agent resolves theaddress information associated with the domain name of the PDF throughthe domain name resolution service, then interacts with the PDF toobtain policy control information, and sends the obtained policy controlinformation to the access gateway.

Step 410: The access gateway sends an acknowledgement message indicatingthe completion of connection setup to the UE.

In the fourth embodiment of the present invention, after receiving thePDF allocation request from the access gateway, the PME obtains thedomain name of the PDF associated with the UE ID (domain name of the PDFaccessed by the core gateway) according to the pre-registered addressinginformation of the PDF; the PME then sends the obtained domain name ofthe PDF to the access gateway. Thus, the core gateway and the accessgateway can access the same PDF to exercise policy control over datastreams in the data connection of the same UE. In other embodiments ofthe present invention, a PDF may also be identified by a domain name,and the address information associated with the domain name may beobtained through the domain name resolution service.

FIG. 5 shows a PDF addressing method according to the fifth embodimentof the present invention. The method is applicable to the SAE network.The PDF is included in the PCRF of the SAE network, and a subscriptionprofile repository (SPR) is a PDF management NE with a built-in PME. TheSAE network supports the UE in connecting to multiple PDN networks, andthe UE sets up two IP-CAN connections with two PDN networks throughgateway 1 of a first PDN (PEP) and gateway 2 of a second PDN (PEP).Thus, a same PDF is used to manage two IP-CAN connections of the sameUE. The method includes the following steps:

Step 501: The UE sends a connection setup request to the gateway 1 toaccess the first PDN.

Step 502: The gateway 1 sends a policy control request containing the UEID to the PCRF.

Step 503: The PCRF generates policy control information according to thepolicy control request, and registers the addressing information of thePCRF with the SPR.

The addressing information of the PCRF is an association between theaddress of the PCRF and the UE ID.

Step 504: The PCRF sends the policy control information to the gateway1.

Step 505: The gateway 1 sends an acknowledgement message indicating thecompletion of connection setup to the UE.

Step 506: The UE sends a connection setup request to the gateway 2 toaccess the second PDN.

Step 507: The gateway 2 accesses the SPR to request the address of thePCRF.

Specifically, this step is as follows: The gateway 2 sends a PDF addressallocation request that contains the UE ID; the SPR obtains the addressof the PCRF associated with the UE ID according to the pre-registeredaddressing information of the PCRF.

Step 508: The gateway 2 interacts with the PCRF to obtain policy controlinformation.

Step 509: The gateway 2 sends an acknowledgement message indicating thecompletion of connection setup to the UE.

In the fifth embodiment of the present invention, a same PCRF may beused to manage more than two IP-CAN connections of the same UE, whichdoes not affect the implementation of the present invention.

In the fifth embodiment of the present invention, after receiving thePDF address allocation request from the gateway 2, the SPR with abuilt-in PME obtains the address of the PDF associated with the UE ID(address of the PDF accessed by the gateway 1) according to thepre-registered addressing information of the PDF; the SPR then sends theobtained address of the PDF to the gateway 2. Thus, the gateway 1 andgateway 2 can access the same PDF. So multiple data connections of thesame UE can only use the same PDF. In this case, only one PDF isrequired to maintain the user information of the UE, which reduces theuser information maintenance workload of the PDF in the whole network.

FIG. 6 shows a PDF addressing method according to the sixth embodimentof the present invention. The method is applicable to a scenario where ahandover between an SAE network and another network occurs. The UE isconnected to the PDN through a mobility management entity (MME) and SAEnetwork gateways on the 3GPP access network, where the SAE networkgateways include a serving gateway (PEP) and a PDN GW (PEP). The UE isconnected to the PDN through the access gateway and PDN GW of the SAEnetwork on the non-3GPP access network. The method includes thefollowing steps:

Step 601: The UE sends a data connection setup request to the MME.

Step 602: The MME obtains user subscription information from a userinformation server, for example, a home subscriber server (HSS) or anauthentication, authorization and accounting (AAA) server, and performsauthentication and authorization on the user according to the usersubscription information. The MME sends a PCRF allocation request whichcontains the UE ID to the user information server. The PME in the userinformation server checks whether the addressing information of the PCRFis already available according to the UE ID; if already available, thePME obtains the address of the PCRF associated with the UE ID accordingto the addressing information of the PCRF; if the PME does not registerthe addressing information of the PCRF, the PME allocates an address ofa PCRF.

The addressing information of the PCRF in this step may be anassociation between the UE ID and the address of the PCRF, or anassociation among the UE ID, the PDN ID and the address of the PCRF.

In this step, the PME may store the association between the allocatedaddress of the PDF and the UE ID as the addressing information of thePDF, or the association among the allocated address of the PDF, the UEID and the PDN ID as the addressing information of the PDF, or the MMEregisters the addressing information with the PME after step 607.

Step 603: The MME sends a data connection setup request containing theaddress of the PCRF to the 3GPP serving gateway.

Step 604: The 3GPP serving gateway interacts with the 3GPP PDN GW, andsets up a data channel between the serving gateway and the PDN GW.

Step 605: The 3GPP serving gateway sends a PCRF allocation request tothe user information server. The PME in the user information serverchecks whether the addressing information of the PCRF is alreadyavailable according to the UE ID; if already available, the PME obtainsthe address of the PCRF associated with the UE ID according to theaddressing information of the PCRF; if the PME does not register theaddressing information of the PCRF, the PME allocates an address of aPCRF, and stores the addressing information of the PCRF.

The address of the PCRF may be allocated either in step 602 or step 605.If step 605 is executed, the address of the PCRF will not be containedin the data connection setup request that the MME sends to the 3GPPserving gateway in step 603.

Step 606: The 3GPP serving gateway interacts with the PCRF to obtainpolicy control information.

Step 607: The 3GPP serving gateway sends an acknowledgement messageindicating the completion of data connection setup to the MME.

Step 608: The MME sends an acknowledgement message indicating thecompletion of data connection setup to the UE.

The serving gateway may select PCRF by itself, and the 3GPP servinggateway may makes the address of the PCRF contained in theacknowledgement message indicating the completion of data connectionsetup in step 607, and the MME may register the addressing informationof the PCRF with the PME; or, when the PME allocates addresses ofmultiple available PCRFs in step 602, the MME may select an address of aone PCRF and send it to the 3GPP serving gateway in step 603, and theMME registers the addressing information of the selected PCRF with thePME after receiving the acknowledgement message indicating thecompletion of data connection setup from the 3GPP serving gateway instep 607.

Step 609: The UE accesses a non-3GPP access network, and sends a dataconnection setup request to the non-3GPP access gateway.

Step 610: The non-3GPP access gateway interacts with the userinformation server to request the address of the PCRF.

Specifically, this step is as follows: The non-3GPP access gateway sendsa PDF address allocation request to the user information server; the PMEin the user information server checks whether the addressing informationof the PCRF is already available according to the UE ID; if alreadyavailable, the PME obtains the address of the PCRF associated with theUE ID according to the addressing information of the PCRF; if the PMEdoes not register the addressing information of the PCRF, the PMEallocates an address of a PCRF and stores the addressing information ofthe PCRF.

Step 611: The non-3GPP access gateway interacts with the PCRF to obtainpolicy control information.

Step 612: The non-3GPP access gateway interacts with the 3GPP servinggateway, and sets up a data connection with the serving gateway.

Step 613: The non-3GPP access gateway sends an acknowledgement messageindicating the completion of data connection setup to the UE.

In the sixth embodiment of the present invention, when the UE is handedover from one network to another network, the PME obtains the address ofthe PDF (address of the PDF accessed by the PEP on the source network)associated with the UE ID according to the pre-registered addressinginformation of the PDF after receiving the PDF address allocationrequest from the PEP on the target network, and sends the obtainedaddress of the PDF to the PEP on the target network. Thus, the dataconnection of the target network can use the same PDF as that of thetarget network, which avoids the failure of data service transmissiondue to an inter-network handover.

FIG. 7 shows a PDF addressing method according to the seventh embodimentof the present invention. The method is applicable to a scenario inwhich the UE accesses a PDN by setting up data connections with avisited gateway and a home gateway when roaming. The data connectionwith the visited gateway is used for optimizing the route of the UE inthe visited network. The method may ensure that these two dataconnections use the same visited PDF and home PDF.

Step 701: The UE sends a connection setup request to the visited gateway(PEP).

Step 702: The visited gateway interacts with the visited PME to requestthe address of a visited PDF; the visited gateway requests the addressof a home PDF by the interaction with the home PME through the visitedPME.

Step 703: The visited gateway sends a policy control request to thevisited PDF. The policy control request includes the UE ID, PDN ID andaddress of the home PDF.

Step 704: The visited PDF obtains the policy control information of thehome network from the home PDF.

Step 705: The visited PDF generates policy control information of thevisited network, negotiates with the policy control information of thehome network to obtain policy control information, and sends theobtained policy control information to the visited gateway.

Step 706: The visited gateway interacts with the visited PME, andregisters the addressing information of the visited PDF with the visitedPME.

The visited gateway sends a registration request containing the UE ID,address of the visited PDF and address of the home PDF to the visitedPME during the interaction, which may also contain the PDN ID. Thevisited PME registers the addressing information of the visited PDFaccording to the registration request. The addressing information of thevisited PDF is an association between the UE ID and the address of thevisited PDF, or an association among the UE ID, the PDN ID and theaddress of the visited PDF.

Step 707: The visited PME interacts with the home PME, and registers theaddressing information of the home PDF with the home PME.

Specifically, this step is as follows: The visited PME sends aregistration request containing the addressing information of the homePDF to the home PME, where the registration request includes the UE IDand address of the home PDF; the home PME registers the addressinginformation of the home PDF according to the registration request.

Step 708: The visited gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

Step 709: The UE sends a connection setup request to the visited gateway(PEP).

Step 710: The visited gateway sends a visited PDF address allocationrequest to the visited PME; the visited PME checks whether theaddressing information of the visited PDF is already available accordingto the UE ID; if already available, the visited PME obtains the addressof the visited PDF associated with the UE ID and sends it to the visitedgateway; otherwise, the visited PME allocates an address of a visitedPDF.

Step 711: The visited gateway obtains policy control information fromthe visited PDF.

Step 712: The visited gateway registers the addressing information ofthe visited PDF with the visited PME.

Specifically, this step is as follows: The visited gateway sends aregistration request containing the UE ID and address of the visited PDFto the visited PME, where the registration request may further includethe PDN ID. The visited PME registers the addressing information of thevisited PDF according to the registration request. The addressinginformation of the visited PDF is an association between the UE ID andthe address of the visited PDF, or an association among the UE ID, thePDN ID and the address of the visited PDF.

If the visited PME finds the addressing information of the PDF accordingto the UE ID in step 710, step 712 is omitted.

Step 713: The visited gateway sends a connection setup request thatcontains the policy control information of the visited network to thehome gateway.

Step 714: The home gateway sends a home PDF address allocation requestto the home PME; the home PME checks whether the addressing informationof the home PDF is already available according to the UE ID; if alreadyavailable, the home PME obtains the address of the home PDF associatedwith the UE ID and sends it to the home gateway; otherwise, the home PMEallocates an address of a home PDF.

Step 715: The home gateway obtains policy control information from thehome PDF.

Step 716: The home gateway registers the addressing information of thehome PDF with the home PME.

If the home PME finds the addressing information of the PDF according tothe UE ID in step 714, step 716 is omitted.

Specifically, this step is as follows: The home gateway sends aregistration request containing the addressing information of the homePDF to the home PME; the home PME registers the addressing informationof the home PDF according to the registration request.

Step 717: The home gateway performs policy negotiation on the obtainedpolicy control information of the home network and the policy controlinformation of the visited network to obtain the policy controlinformation, and sends an acknowledgement message indicating thecompletion of connection setup to the visited gateway, where theacknowledgement message contains the obtained policy controlinformation.

Step 718: The visited gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

The preceding steps 701 to 709 describe a process of setting up a dataconnection between the UE and the visited gateway. The preceding steps710 to 718 describe a process of setting up a data connection betweenthe UE and the home gateway through the visited gateway. Either of thetwo data connections may be set up earlier. If the visited PME registersthe addressing information of the visited PDF in the earlier dataconnection process, the visited PME does not need to register theaddressing information of the visited PDF in the later data connectionprocess. Similarly, if the home PME registers the addressing informationof the home PDF in the earlier data connection process, the home PMEdoes not need to register the addressing information of the home PDF inthe later data connection process, which may also achieve the objectiveof the present invention.

In the seventh embodiment of the present invention, a same PME may alsobe used to register the addressing information of the PDF. In this case,the addressing information of the PDF is a mapping relation among theaddress of the home PDF, the address of the visited PDF and the UE ID,which may also achieve the objective of the present invention.

In the seventh embodiment of the present invention, the visited PMEregisters the addressing information of the visited PDF, and the homePME registers the addressing information of the home PDF. In this case,when the UE sets up data connections with the visited gateway and homegateway to access the PDN, the UE can obtain the addresses of thevisited PDF and home PDF that are accessed through the earlier dataconnection in the later data connection. Thus, the visited PDF and homePDF used by these two data connections are the same, so that multipledata connections of the same UE can use the same home PDF.

FIG. 8 shows a PDF addressing method according to the eighth embodimentof the present invention. The method is applicable to a scenario inwhich the UE accesses a PDN by setting up data connections with avisited gateway and a home gateway when roaming. The data connectionwith the visited gateway may be used for optimizing the route of the UEin the visited network. The method may ensure that these two dataconnections use the same home PDF. The method includes the followingsteps:

Step 801: The UE sends a data connection setup request to the MME oraccess gateway.

Step 802: The MME or access gateway sends a connection setup request tothe visited gateway.

Step 803: The visited gateway sends a connection setup request to thehome gateway.

Step 804: The home gateway interacts with the PME to request the addressof a home PCRF.

Specifically, this step is as follows: The home gateway sends a PDFaddress allocation request to the PME, which contains the UE ID, or theUE ID and PDN ID; the PME checks whether the addressing information ofthe PCRF is already available according to the UE ID, or the UE ID andPDN ID; if already available, the PME finds the address of the home PCRFassociated with the UE ID, and sends it to the home gateway; otherwise,the PME allocates an address of a proper PCRF, and returns the addressof the PCRF to the home gateway or provides the home gateway withaddresses of multiple PCRFs for selection.

Step 805: The home gateway interacts with the home PCRF to obtain policycontrol information.

Step 806: The home gateway registers the addressing information of thePCRF with the PME.

Step 807: The home gateway sends an acknowledgement message indicatingthe completion of connection setup to the visited gateway.

Step 808: The visited gateway sends an acknowledgement messageindicating the completion of connection setup to the MME or accessgateway.

Step 809: The MME or access gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

Step 810: The UE sends a data connection setup request to the MME oraccess gateway.

Step 811: The MME or access gateway sends a connection setup request tothe visited gateway.

Step 812: The visited gateway interacts with the PME to request theaddress of the home PCRF.

Specifically, this step is as follows: The visited gateway sends a PDFaddress allocation request to the PME, which contains the UE ID; the PMEchecks whether the addressing information of the PCRF is alreadyavailable according to the UE ID; if already available, the PME findsthe address of the home PCRF associated with the UE ID, and sends it tothe visited gateway; otherwise, the PME allocates an address of a properPCRF, and returns the address of the PCRF to the visited gateway orprovides the visited gateway with addresses of multiple PCRFs forselection.

Step 813: The visited gateway sends a policy control request to thevisited PCRF. The policy control request includes the UE ID, PDN ID andaddress of the home PDF.

Step 814: The visited PCRF obtains the policy control information of thehome network from the home PCRF.

Step 815: The visited PCRF generates policy control information of thevisited network, obtains policy control information through negotiationwith the policy control information of the home network, and sends theobtained policy control information to the visited gateway.

Step 816: The visited gateway registers the addressing information ofthe home PCRF with the PME.

Step 817: The visited gateway sends an acknowledgement messageindicating the completion of connection setup to the MME or accessgateway.

Step 818: The MME or access gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

Step 812 may also be replaced as follows: The visited PCRF sends a PDFaddress allocation request to the PME after the visited gateway sends apolicy control request to the visited PCRF; after obtaining the IDinformation of the home PCRF, the visited PCRF executes step 814 toobtain policy control information, so that the visited PCRF is the sameas the home PDF accessed by the home gateway in step 805.

Similarly, step 816 may be replaced as follows: After step 814, thevisited PCRF registers the addressing information of the home PCRF withthe PME.

The preceding steps 801 to 809 describe a process of setting up a dataconnection between the UE and the home gateway. The preceding steps 810to 818 describe a process of setting up a data connection between the UEand the visited gateway. Either of the two data connections may be setup earlier. If the addressing information of the home PCRF is registeredin the earlier data connection process, the addressing information ofthe home PCRF does not need to be registered in the later dataconnection process, which may also achieve the objective of the presentinvention.

In the eighth embodiment of the present invention, the PME registers theaddressing information of the home PCRF. In this case, when the UEaccesses a PDN by setting up data connections with the visited gatewayand home gateway, the UE can obtain the address of the home PCRF that isaccessed in the earlier data connection in the later data connectionprocess, thus ensuring that these two data connections of the same UEuse the same home PCRF.

FIG. 9 shows a PDF addressing method according to the ninth embodimentof the present invention. The method is applicable to a scenario inwhich a home gateway needs to connect to a home PDF to obtain policycontrol information of the home network and a visited gateway also needsto contact the home PDF for policy negotiation when the UE is roaming.That is, the visited gateway and home gateway correspond to the samedata connection, and should access the same home PDF. The methodincludes the following steps:

Step 901: The UE sends a connection setup request to the MME.

Step 902: The MME sends a connection setup request to the visitedgateway.

Step 903: The visited gateway sends a policy control request to thevisited PDF. The policy control request includes the UE ID and PDN ID.

Step 904: The visited PDF obtains the policy control information of thehome network from the home PDF.

Step 905: The visited PDF generates policy control information of thevisited network, obtains policy control information through negotiationwith the policy control information of the home network, and sends theobtained policy control information and address of the home PDF to thevisited gateway.

Step 906: The visited gateway registers the addressing information ofthe home PDF with the PME.

Specifically, this step is as follows: The visited gateway sends aregistration request containing the addressing information of the homePDF to the PME; the PME registers the addressing information of the homePDF according to the registration request.

Step 907: The visited gateway sends a connection setup request to thehome gateway.

Step 908: The home gateway interacts with the PME to request the addressof home PDF.

Specifically, this step is as follows: The home gateway sends a PDFaddress allocation request containing the UE ID to the PME; the PMEobtains the address of the PDF associated with the UE ID according tothe pre-registered addressing information of the PDF, and sends theobtained address of the PDF to the home gateway.

Step 909: The home gateway obtains policy control information of thehome network from the home PDF.

Step 910: The home gateway sends an acknowledgement message indicatingthe completion of connection setup to the visited gateway.

Step 911: The visited gateway sends an acknowledgement messageindicating the completion of connection setup to the MME.

Step 912: The MME sends an acknowledgement message indicating thecompletion of connection setup to the UE.

In the ninth embodiment of the present invention, the PME registers theaddressing information of the home PCRF, and the home gateway obtainsthe address of the home PCRF from the PME. Thus, when the visitedgateway and the home gateway correspond to the same data connection,they can access the same home PDF.

FIG. 10 shows a PDF addressing method according to the tenth embodimentof the present invention. The method is applicable to a scenario inwhich the UE moves from one visited network to another visited networkand uses a route optimization policy for the data connection in thevisited network. The method includes the following steps:

Step 1001: The UE sends a connection setup request to a first visitedgateway.

Step 1002: The first visited gateway interacts with the PME to requestthe address of the home PDF.

Step 1003: The first visited gateway sends a policy control requestcontaining the address of the home PDF to a first visited PDF.

Step 1004: The first visited PDF obtains policy control information ofthe home network from the home PDF.

Step 1005: The first visited PDF generates policy control information ofthe visited network, obtains policy control information throughnegotiation with the policy control information of the home network, andsends the obtained policy control information to the first visitedgateway.

Step 1006: The home PDF registers the addressing information of the homePDF with the PME.

Specifically, this step is as follows: The home PDF sends a registrationrequest containing the addressing information of the home PDF to thePME; the PME registers the addressing information of the PDF accordingto the registration request.

Step 1007: The first visited gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

Then, the UE roams to a second visited network.

Step 1008: The UE sends a connection setup request to a second visitedgateway.

Step 1009: The second visited gateway obtains the address of the homePDF from the PME according to the UE ID.

Specifically, this step is as follows: The second visited gateway sendsa PDF address allocation request containing the UE ID to the PME; ThePME obtains the address of the PDF according to the pre-registeredaddressing information of the PDF, and sends the obtained address of thePDF to the second visited gateway.

Step 1010: The second visited gateway sends a policy control requestcontaining the address of the home PDF to the second visited PDF.

Step 1011: The second visited PDF obtains policy control information ofthe home network from the home PDF.

Step 1012: The second visited PDF generates policy control informationof the visited network, obtains policy control information throughnegotiation with the policy control information of the home network, andsends the obtained policy control information to the second visitedgateway.

Step 1013: The second visited gateway sends an acknowledgement messageindicating the completion of connection setup to the UE.

In the tenth embodiment of the present invention, the first visitedgateway registers the addressing information of the home PCRF with thePME, and the second visited gateway obtains the address of the home PCRFfrom the PME. This can ensure that the first visited gateway and thesecond visited gateway access the same home PCRF and use the policycontrol information generated by the same home PCRF. Thus, a policy andcharging control (PCC) architecture may be used to control whichservices need to undergo route optimization and which services need tobe routed back to the home network.

FIG. 11 shows a PDF addressing method according to the eleventhembodiment of the present invention. The method is applicable to ascenario in which the UE initiates a service setup request after settingup data connections and the application function sets up a service datachannel for the data service of the UE to ensure the quality of service(QoS). The method includes the following steps:

Step 1101: The PDN GW, as the PEP, obtains policy control informationfrom the PDF, sets up a data connection with the UE, and registers theaddressing information of the PDF with the PME.

Step 1102: The UE sends a service setup request containing the UE ID tothe application function.

Step 1103: The application function obtains the address of the PDF fromthe PME according to the UE ID.

Specifically, this step is as follows: The application function sends aPDF address allocation request containing the UE ID to the PME; the PMEobtains the address of the PDF according to the pre-registeredaddressing information of the PDF, and sends the obtained address of thePDF to the application function.

Step 1104: The application function sends service information asrequested by the UE to the PDF.

Step 1105: The PDF generates policy control information applicable tothe service according to the service information as requested by the UE,and sends the policy control information to the PDN GW which acts as thePEP.

Step 1106: The PDN GW sets up a service data channel with the UEaccording to the policy control information applicable to the service.

In the eleventh embodiment of the present invention, after receiving aPDF address allocation request from the application function, the PMEobtains the address of the PDF associated with the UE ID according tothe pre-registered addressing information of the PDF; then the PME sendsthe obtained address of the PDF to the application function so that theapplication function can send service information to and access the PDFused in the previous connection.

In the preceding embodiment, the PDF may be located in the PCRF. In thiscase, the addressing information of the PDF is the addressinginformation of the PCRF, which is an association between the UE ID andthe address of the PCRF or an association among the address of the PCRF,the UE ID and the PDN ID.

In the preceding embodiment, the NE with the PME functions is called aPME. The NE may be an SPR or an AAA/HSS, which does not affect theimplementation of the present invention.

It is understandable to those skilled in the art that all or part of thesteps in the preceding embodiments may be implemented by hardwareinstructed by a program. The program may be stored in a computerreadable storage medium such as a read-only memory (ROM), a randomaccess memory (RAM), a magnetic disk or a compact disk (CD).

In the preceding embodiments, a PDF may be identified by the domain nameor address of the PDF, or a PDF may be identified by the combination ofthe domain name and address of the PDF or by other IDs, which may alsoachieve the objective of the present invention.

FIG. 12 shows an NE according to the twelfth embodiment of the presentinvention. The NE may be located in the SPR or AAA/HSS and includes:

a PDF request receiving unit 1201, configured to receive a PDFallocation request containing a UE ID;

a PDF ID information obtaining unit 1202, configured to obtain IDinformation of a PDF associated with the UE ID according topre-registered addressing information of the PDF, where the addressinginformation of the PDF is an association between the UE ID and the IDinformation of the PDF, and the PDF associated with the UE ID isaccessed by a first NE; and

a PDF ID information outputting unit 1203, configured to output theobtained ID information of the PDF.

The NE further includes:

a registration request receiving unit 1204, configured to receive aregistration request containing the addressing information of the PDF;and

a registering unit 1205, configured to register the addressinginformation of the PDF after receiving the registration requestcontaining the addressing information of the PDF.

FIG. 13 shows an NE according to the thirteenth embodiment of thepresent invention. The NE may be located in the SPR or AAA/HSS andincludes:

a PDF request receiving unit 1301, a PDF ID information obtaining unit1302, and a PDF ID information outputting unit 1303, functions of andconnection relations among which are the same as those in the eleventhembodiment.

The NE further includes:

an allocating unit 1304, configured to allocate the PDF; and

a registering unit 1305, configured to register the addressinginformation of the PDF according to the ID information of the allocatedPDF and the UE ID.

After receiving a PDF allocation request, the NEs according to thetwelfth and thirteenth embodiments of the present invention obtain andoutput the ID information of the PDF associated with the UE ID accordingto the pre-registered addressing information of the PDF. Thus, the NErequesting a PDF can obtain the ID information of the PDF, and accessthe same PDF as other NEs that serve the UE. When the same UE has set uptwo data connections, an ongoing data connection or data service channelcan use the same PDF as that used in the previous connections to performpolicy control.

FIG. 14 shows a network system according to the fourteenth embodiment ofthe present invention. The network system includes a PME and a secondNE.

The PME is configured to: receive a PDF allocation request containing aUE ID from the second NE; obtain the ID information of the PDFassociated with the UE ID according to the pre-registered addressinginformation of the PDF, where the addressing information of the PDF isan association between the UE ID and the ID information of the PDF, andthe PDF associated with the UE ID is accessed by the first NE; and sendthe obtained ID information of the PDF to the second NE.

The second NE is configured to: send a PDF allocation request to thePME, and receive the ID information of the PDF from the PME.

The network system further includes:

a first NE, configured to send a registration request containing theaddressing information of the PDF to the PME; and

the PME, further configured to register the addressing information ofthe PDF after receiving the registration request.

Or the network system further includes:

a first NE, configured to send a PDF allocation request to the PME; and

the PME, further configured to: allocate a PDF for the first NE whendetermining that no addressing information of the PDF is registeredaccording to the UE ID contained in the PDF allocation request, andregister the addressing information of the allocated PDF.

The first NE may be an access gateway, a PDN GW or a visited PDF, andthe second NE may be an access gateway, a PDN GW, a visited PDF or anapplication function. The PME may be an independent physical entity orlocated in a physical entity with an SPR or an AAA/HSS.

After receiving a PDF allocation request, the PME according to thefourteenth embodiment of the present invention obtains the IDinformation of the PDF associated with the UE ID according to thepre-registered addressing information of the PDF, and sends the obtainedID information of the PDF to the second NE. Thus, the second NE canobtain the ID information of the PDF, and access the same PDF as otherNEs that serve the UE. When the same UE has set up two data connections,an ongoing data connection can use the same PDF as that used in theprevious connections to perform policy control.

Detailed above are a PDF addressing method, an NE and a network systemaccording to the embodiments of the present invention. It is apparentthat those skilled in the art can make various modifications andvariations to the invention without departing from the spirit and scopeof the invention. In conclusion, the present invention is not limited tothe contents of the specifications.

What is claimed is:
 1. A policy decision function (PDF) addressingmethod, comprising: receiving, by a policy management entity (PME), afirst PDF allocation request from an Access gateway, wherein the firstPDF allocation request contains a user equipment (UE) identifier (ID);allocating a PDF in response to the first PDF allocation request,wherein the allocated PDF is used to generate policy controlinformation; registering, by the PME, addressing information of theallocated PDF, wherein the addressing information of the allocated PDFincludes an association between the UE ID and ID information of theallocated PDF associated with the UE ID, wherein the ID information ofthe allocated PDF associated with the UE ID includes a domain name oraddress information of the allocated PDF associated with the UE ID;receiving, by the PME, a second PDF allocation request from a Coregateway, wherein the second PDF allocation request includes the UE ID;obtaining, by the PME, the ID information of the allocated PDFassociated with the UE ID from the registered addressing information ofthe allocated PDF; and sending, by the PME, the obtained ID informationof the allocated PDF associated with the UE ID to the Core gateway.
 2. Anon-transitory computer readable storage medium encoded with computerprogram stored thereon for: receiving a first policy decision function(PDF) allocation request from an Access gateway and allocating a PDF inresponse to a first PDF allocation request, wherein the first PDFallocation request includes a user equipment (UE) identifier (ID),wherein the allocated PDF is used to generate policy controlinformation; registering addressing information of the allocated PDF,wherein the addressing information of the allocated PDF includes anassociation between the UE ID and ID information of the PDF associatedwith the UE ID, wherein the ID information of the allocated PDFassociated with the UE ID includes a domain name or address informationof the allocated PDF associated with the UE ID; receiving a second PDFallocation request from a Core gateway, wherein the second PDFallocation request includes the UE ID; obtaining the ID information ofthe allocated PDF associated with the UE ID from the registeredaddressing information of the allocated PDF; and outputting the obtainedID information of the allocated PDF associated with the UE ID to theCore gateway.
 3. A policy decision function (PDF) addressing method,comprising: receiving, by a policy management entity (PME), a first PDFallocation request from an Access gateway, wherein the first PDFallocation request contains a user equipment (UE) identifier (ID) and apublic data network (PDN) ID; allocating a PDF in response to the firstPDF allocation request, wherein the allocated PDF is used to generatepolicy control information; registering, by the PME, addressinginformation of the allocated PDF, wherein the addressing information ofthe allocated PDF includes an association of the UE ID, the PDN ID, andID information of the PDF associated with the UE ID and the PDN ID,wherein the ID information of the allocated PDF associated with the UEID and the PDN ID includes a domain name or address information of theallocated PDF associated with the UE ID and the PDN ID; receiving, bythe PME, a second PDF allocation request from a Core gateway, whereinthe second PDF allocation request includes the UE ID and the PDN ID;obtaining, by the PME, the ID information of the allocated PDFassociated with the UE ID and the PDN ID from the registered addressinginformation of the allocated PDF; and sending, by the PME, the obtainedID information of the allocated PDF associated with the UE ID and thePDN ID to the Core gateway.